Coccidiosis in Poultry

Poultry industry contributes 1% total GDP of our country. It provides sustainable employment  throughout the year. Poultry is also a source of protein supplementation in rural parts of India. Back yard poultry is the important source of income and household protein source. Coccidiosis is an important disease of poultry having economical importance in broilers under deep litter and backyard type of system caused by Eimeria species belongs to family Eimeridae Genus Eimeria. Eimeria are intracellular single cell protozoal organisms which are highly host specific and organ specific. Chicken and Turkey are highly susceptible for Coccidial infections. Disease is worldwide in distribution young birds of age group 3-8 weeks are highly susceptible. No cross immunity will be observed between the species. Subclinical infection  will cause poor feed intake and weight gain. All breeds of birds are susceptible. Disease causes severe economical loss in early age group of birds and predisposes secondary bacterial infections like E Coli, Salmonella and Clostridium will causes enteritis and mixed infection. Coccidial infection in birds will be most of time opportunistic and it will be self limiting. Disease is reported in wild birds, game birds and domestic birds. Mixed coccidial infestation are more common.

Predisposing factors for the Coccidial infestation in birds.

1. Poor hygiene in the farm.
2. Wet litter.
3. Deep litter system.
4. Inadequate ventilation.
5. Over crowding/ over stocking.
6. Concurrent diseases.
7. Poor management practice in the farm.
8. Poor nutritional status.

Epidemiology

Disease is endemic in India, intensive rearing system is having higher incidence. Younger birds will be affected more. Concurrent disease and poor litter hygiene will increases the risk of infection.

Transmission

Coccidiosis spreads fast in deep litter rearing system, transmission occurs through contaminated feed and water, faeco-oral route Incubation period 4-7 days. Coccidia will multiply in the intestine and produces disease characterized by enteritis, tissue damage in intestine, malabsorption, sudden death of birds, droppings may contain blood. Clinical signs including severe diarrhea, high mortality, reduced feed and water intake, decreased egg production, stunted growth, weight loss, bloody droppings, anorexia, rough feathers and anaemia. Eimeria tenella, E. necatrix and E. brunette will causes hemorrhagic enteritis. Other species will cause enteritis.

Clinical signs

Passing of blood mixed droppings, mucosal shreds in faecal droppings, dehydration, symptoms of anaemia, hurried respiration, dull n depressed birds, roughened feathers, poor feed conversion ratio and gain in body weight, most of the time birds will recover but in case of severe infestation and due to secondary bacterial infection due to Clostridium causes necrotic enteritis and death occures due to dehydration.

PM lesions

Eimeria tenella causes haemorrhagic typhlitis, bloody caecum, E. necatrix causes salt and pepper appearance of intestine, E. brunette causes lesions in lower part of intestine, rectum, caeca and cloeca. Affected birds will show enteritis, ballooning of intestine, intestinal bleeding lesions, mucoidal accumulation in intestine

Diagnosis                                                

1. Faecal smear examination under low power in microscope will revels presence of oocyst in the smear confirms the bird dropping with Eimeria species infested to birds.
2. Sudden onset of diarrhea and dysentery.
3. History of low feed convertion rate, passing watery droppings mixed with mucosal shreads and blood.
4. In post mortem examination revels presence of enteritis lesions in intestine with mucus accumulation, haemorrhagic enteritis, salt and pepper like lesions in various part of intestine as per the location and species of Eimeria infested in intestine, thickening of wall of intestine, petichial haemorrhages and dehydrated pale carcass.

Differential diagnosis

1. Colibacillosis
2. Salmonellosis
3. Necrotic enteritis

Treatment

Once the disease is diagnosed, treatment should be given immediately and removal of stress factor should be done early. Drugs including Sulpha group, Nitroferozone compounds, Amprolium compounds, Clopidol group, Monensin, and Tetracycline compounds should be given as per the recommendation of Veterinarian. Prophylaxis dosage should be given in endemic areas in drinking water. Feed additive Coccidiostats should be used in suspected farms.

Control

1. Avoid any type of stress to birds.
2. Provide clean feed and water to birds.
3. Avoid rearing of mixed age group birds rearing in same unit.
4. Avoid mixed species of birds rearing.
5. Following good bio-security measures in the farm.
6. Quarantine should be followed strictly in the farm.
7. Isolate and treat the affected birds.
8. Regular vaccination and deworming should be followed.
9. Turning of litter regularly.
10. Prophylaxis medication.
11. Proper disposal of litter material.

Reference

1. Overview of coccidiosis in poultry, MSD Veterinary Manual.
2. Coccidiosis in poultry, thepoultrysite.com